Expression of arf tumor suppressor in spermatogonia facilitates meiotic progression in male germ cells

The mammalian Cdkn2a (Ink4a-Arf) locus encodes two tumor suppressor proteins (p16Ink4a and p19Arf) that respectively enforce the anti-proliferative functions of the retinoblastoma protein (Rb) and the p53 transcription factor in response to oncogenic stress. Although p19Arf is not normally detected in tissues of young adult mice, a notable exception occurs in the male germ line, where Arf is expressed in spermatogonia, but not in meiotic spermatocytes arising from them. Unlike other contexts in which the induction of Arf potently inhibits cell proliferation, expression of p19Arf in spermatogonia does not interfere with mitotic cell division. Instead, inactivation of Arf triggers germ cell-autonomous, p53-dependent apoptosis of primary spermatocytes in late meiotic prophase, resulting in reduced sperm production. Arf deficiency also causes premature, elevated, and persistent accumulation of the phosphorylated histone variant H2AX, reduces numbers of chromosome-associated complexes of Rad51 and Dmc1 recombinases during meiotic prophase, and yields incompletely synapsed autosomes during pachynema. Inactivation of Ink4a increases the fraction of spermatogonia in S-phase and restores sperm numbers in Ink4a-Arf doubly deficient mice but does not abrogate γ-H2AX accumulation in spermatocytes or p53-dependent apoptosis resulting from Arf inactivation. Thus, as opposed to its canonical role as a tumor suppressor in inducing p53-dependent senescence or apoptosis, Arf expression in spermatogonia instead initiates a salutary feed-forward program that prevents p53-dependent apoptosis, contributing to the survival of meiotic male germ cells

Standardisation framework for the Maudsley staging method for treatment resistance in depression

Background: Treatment-resistant depression (TRD) is a serious and relatively common clinical condition. Lack of consensus on defining and staging TRD remains one of the main barriers to understanding TRD and approaches to intervention. The Maudsley Staging Method (MSM) is the first multidimensional model developed to define and stage treatment-resistance in “unipolar depression”. The model is being used increasingly in treatment and epidemiological studies of TRD and has the potential to support consensus. Yet, standardised methods for rating the MSM have not been described adequately. The aim of this report is to present standardised approaches for rating or completing the MSM. Method: Based on the initial development of the MSM and a narrative review of the literature, the developers of the MSM provide explicit guidance on how the three dimensions of the MSM–treatment failure, severity of depressive episode and duration of depressive episode– may be rated. Result: The core dimension of the MSM, treatment failure, may be assessed using the Maudsley Treatment Inventory (MTI), a new method developed for the purposes of completing the MSM. The MTI consists of a relatively comprehensive list of medications with options for rating doses and provisions treatment for multiple episodes. The second dimension, severity of symptoms, may be assessed using simple instruments such as the Clinical Global Impression, the Psychiatric Status Rating or checklist from a standard diagnostic checklist. The standardisation also provides a simple rating scale for scoring the third dimension, duration of depressive episode. Conclusion: The approaches provided should have clinical and research utility in staging TRD. However, in proposing this model, we are fully cognisant that until the pathophysiology of depression is better understood, staging methods can only be tentative approximations. Future developments should attempt to incorporate other biological/ pathophysiological dimensions for staging

Low-density lipoprotein cholesterol outcomes post-non-PCSK9i lipid-lowering therapies in atherosclerotic cardiovascular disease and probable heterozygous familial hypercholesterolemia patients

Chi-Chang Chen,1 Pallavi B Rane,2 Dionne M Hines,1 Jeetvan Patel,2 David J Harrison,2 Rolin L Wade1 1IQVIA, Plymouth Meeting, PA, USA; 2Amgen Inc., Thousand Oaks, CA, USA Background: This study evaluated the proportion of patients with atherosclerotic cardiovascular disease (ASCVD) and probable heterozygous familial hypercholesterolemia (HeFH) achieving ≥50% reduction in low-density lipoprotein cholesterol (LDL-C) or reaching the LDL-C ≤70 mg/dL threshold, after initiating or modifying statin, and/or ezetimibe therapy. Materials and methods: Adult ASCVD patients with baseline LDL-C >70 mg/dL (index) and a subset of patients with probable HeFH (proxied by LDL-C ≥190 mg/dL) were identified between January 1, 2012, and August 31, 2014, from the IQVIA electronic medical record database. Patients were followed for 12 months pre-index to examine baseline lipid-lowering therapy (LLT) use, and 12 months post index to evaluate treatment modifications and post-treatment LDL-C levels, stratified by type of treatment received and LDL-C levels at baseline. Results: Of the sample of ASCVD patients who initiated treatment post-index (n=111,147), only 7.6% patients achieved a ≥50% reduction from baseline LDL-C and 19.1% of patients reached the LDL-C ≤70 mg/dL threshold. Among treated ASCVD patients who modified therapy post-index (n=75,523), 5.6% achieved a ≥50% reduction in LDL-C, and proportion of patients achieving LDL-C ≤70 mg/dL ranged from 6.9% to 26.7%, depending on the baseline LDL-C levels. Approximately 50% of the untreated probable HeFH patients (n=3,064) initiated LLT; however, the mean (SD) post-treatment LDL-C remained high (136.2 [47.8] mg/dL), with only 4.4% reaching LDL-C ≤70 mg/dL. Of the treated probable HeFH patients (n=1,073), 41.5% modified treatment; 22.1% achieved a ≥50% reduction in LDL-C and 1.1% reached LDL-C ≤70 mg/dL. Conclusion: This study found that most patients had suboptimal LDL-C responses after initiating or modifying standard LLT (statin and/or ezetimibe). More frequent and aggressive lipid management, including increasing statin intensity and alternative therapies, may be needed in patients with ASCVD and probable HeFH to reduce their cardiovascular risk. Keywords: hyperlipidemia, ASCVD, HeFH, LDL-C, statin, lipid-lowering therap

Expression of cytochromes P450 3A and P-glycoprotein in human large intestine in paired tumour and normal samples

Our objective was to investigate the expression of different cytochromes P450 3A (CYP3A4, CYP3A5, and CYP3A7) and P-glycoprotein (ABCBI) genes along the human large intestine in paired tumour and normal samples. Real-time reverse transcriptase-polymerase chain reaction was used to measure CYP3A4-, CYP3A5-, CYP3A7- and ABCB1-specific mRNA expression, and Western blot analysis was used to measure membrane protein levels of CYP3A4/7, CYP3A5 and P-glycoprotein. Levels of mRNA and membrane protein fractions in the large intestine were compared with those of normal human liver. The mRNA expressions of CYP3A4, CYP3A5, CYP3A7 and ABCB1 in the large intestine were found to be highly variable, but overall the levels were significantly lower than those measured in liver (P < 0.0001, P < 0.00 1, P < 0.0001 and P < 0.01, respectively). At the membrane protein level, CYP3A4/7 was detected in all large intestine samples examined and the levels were substantially higher than those of the liver (P < 0.01). Although expression of CYP3A5 was detected in all large intestine samples, in most the levels were too low to allow quantification. P-glycoprotein was readily detected at levels slightly higher than those of liver (P < 0.05). Comparison between paired samples of normal and tumour in large intestine showed no significant differences in either the mRNA or membrane protein levels of these genes. In conclusion, this work suggests a potential role of the large intestine in the absorption and metabolism of xenobiotics and nutrients and no difference in the CYP3A and P-glycoprotein membrane protein fractions and mRNA expression between normal and tumour tissues